3.4 Summary of Developmental Toxicity Data
3.4.2 Experimental Animal Data
Experimental animal studies using multiple dose levels and thus providing dose-response information are summarized in Table 28.
In a number of studies, developing rats were exposed to DEHP and subsequently examined for effects on reproductive and endocrine systems. Five studies were notable, 4 that examined dose-related effects of DEHP exposure, and a fifth study that compared testicular toxicity in rats dosed by the oral versus the IV route. The remaining studies largely focused on mechanisms of developmental reproductive toxicity.
Moore.et.al..(113) orally dosed at least 8 pregnant Sprague-Dawley rats/group with DEHP at 0, 375, 750, or 1500 mg/kg bw/day from GD 3 (GD 1 = day after sperm detected) to PND 21. Parameters associated with sexual development were observed through puberty or adulthood in male and female offspring, and male offspring were tested for sexual behavior. DEHP treatment reduced prenatal maternal weight gain at the middle and high dose. There was no significant effect on implantation sites. Number of pups born was reduced at the high dose, and postnatal survival was decreased at the middle and high dose. The most sensitive DEHP effect on males was an increase in areolae or nipples, which occurred at all dose levels and persisted through adulthood. Incomplete preputial separation, non-descent of testes, and agenesis of anterior prostate and other accessory reproductive organs did not attain statistical significance at the lowest dose level, but the authors considered them to be biologically significant at all doses due to the rarity of the effects. Reproductive effects observed in males exposed to higher doses included reduced anogenital distance, agenesis of seminal vesicle and epididymis, decreased sperm count, and reduced testis, epididymis, glans penis, prostate, and seminal vesicle weights that often persisted through adulthood. In female pups, DEHP treatment had no effect on anogenital distance. Body weight of high-dose females was 68% that of control body weight on the day of vaginal opening, and the effect was statistically significant. The study authors attributed
Appendix II
the effect to DEHP-induced toxicity and not to an estrogenic effect. The study authors identified a LOAEL of 375 mg/kg bw/day for this study based on a significant decrease in anterior prostate weight and increase in permanent nipple retention.
Li.et.al..(119) examined dose-related effects of DEHP on neonatal rat gonocytes and Sertoli cells.
Male Sprague-Dawley rat pups from 4 – 7 litters were pooled and randomly placed into groups of 4 or 5 pups. On PND 3 (day of birth = PND 1), the rats were gavaged with DEHP at 0, 20, 100, 200, or 500 mg/kg bw. Pups were killed 24 hours after dosing, and testes were collected for morphological examination and measurement of Sertoli cell proliferation through BrdU uptake. The time course of effects was examined in a second experiment in which rats were dosed with 0 or 200 mg/kg bw DEHP and examined between 6 and 48 hours following exposure. In rats treated with 100 – 500 mg/kg bw DEHP, there was a dose-related increase in abnormally large gonocytes containing 2 – 4 nuclei.
Multinucleated gonocytes were first detected at 12 hours following exposure to DEHP 200 mg/kg bw, and multinucleated gonocyte numbers increased with time. Sertoli cell proliferation was reduced in rats treated with ≥ 100 mg/kg bw DEHP. Sertoli cell proliferation rebounded at 48 hours following treatment. DEHP did not affect serum FSH levels. [Due.to.reporting.deficiencies,.only.the.Sertoli.
cell.proliferation.data.were.considered.to.be.of.utility.]
Cammack.et.al..(120) examined reproductive development of Sprague-Dawley rats (n = 16/group) treated IV or orally with DEHP. Beginning at 3 – 5 days of age, rats were treated for 19 – 21 days with DEHP at 0, 60, 300, or 600 mg/kg bw/day by IV infusion or 0, 300, 600 mg/kg bw/day by oral gavage. Seven rats/group were scheduled to be killed following the dosing period, and 9/group were scheduled to be held for a recovery period until 90 days of age. Histopathological analyses of prostate, seminal, vesicle, and epididymis and an evaluation of sperm count, motility, and morphology were conducted in the 90-day-old rats. Body weight gain was decreased in rats given 600 mg/kg bw/day by IV infusion and oral gavage. In animals killed immediately after the dosing period, absolute testis weight was significantly reduced at IV and oral doses ≥ 300 mg/kg bw/day. Absolute liver weight was increased in rats given ≥ 300 mg/kg bw/day DEHP by IV infusion. Depletion of germinal epithelium and/or decreased seminiferous tubule diameter was noted in all animals from the 300 and 600 mg/kg bw/day oral and IV dosing groups. Germinal epithelium depletion was rated as moderate (51 – 75%
reduction in thickness) in the 600 mg/kg bw/day oral group and mild (25 – 50% change) in all other groups given ≥ 300 mg/kg bw/day DEHP. Reduced tubule diameter was rated as mild (25 – 50% reduc-tion in diameter) in the 600 mg/kg bw/day oral group and minimal (< 25% change) in the other groups treated with ≥ 300 mg/kg bw/day DEHP. In animals killed at 90 days of age, reduced testicular weights persisted in IV and oral groups given ≥ 300 mg/kg bw/day. The only persisting testicular lesion was a minimal (< 25%) decrease in seminiferous tubular diameter in 2 of 5 rats in the 300 mg/kg bw/day oral group and 3 of 7 rats in the 600 mg/kg bw/day oral group..No prostate, epididymis, or seminal vesicles lesions and no adverse effects on sperm count, motility, or morphology were observed.
A multigeneration DEHP toxicity study conducted in rats also provided some information on devel-opmental toxicity (151). The study is described in detail in Section 4. Briefly, offspring of rats that were fed DEHP in diet at 3000 and 9000 ppm (340 and 1088 mg/kg bw/day) during gestation and lactation experienced an increase in stillbirth, an increase in PND 0 – 4 pup mortality, retardation of F2 pup body weight, altered male anogenital distance, and retained nipples/areolae. A delay in sexual maturation was also noted in F1 offspring at the 9000 ppm exposure level.
Appendix II
The NTP.(114) multigeneration continuous breeding study in rats evaluated effects of DEHP in feed at dose levels of 1.5 (control group exposed to background DEHP levels in feed), 10, 30, 100, 300, 1000, 7500, and 10,000 ppm. Ranges of DEHP intake in the F0, F1, and F2 animals were estimated at 0.09 – 0.12, 0.47 – 0.78, 1.4 – 2.4, 4.8 – 7.9, 14 – 23, 46 – 77, 392 – 592, and 543 – 775 mg/kg bw/day.
[Because.developmental.effects.were.reported,.particularly.on.the.male.reproductive.system,.
the.study.is.included.in.this.section..This.summary.with.additional.details.concerning.the.repro-ductive.effects.is.also.presented.in.Section.4.2.2.2.] The lowest dose level producing dose-related effects in breeding F1 offspring was 7500 ppm, and those effects included decreases in number of live pups/litter, reduced male anogenital distance, and delays in vaginal opening, preputial separa-tion, and age of testicular descent. Additional effects noted in the F1 offspring from the 10,000 ppm group included decreased live pup weight at birth and during the lactation period and increased ratio of female anogenital distance to body weight..[The.Expert.Panel.carefully.considered.the.finding.
of.small.reproductive.organ.sizes.by.gross.observations.in.both.F1.and.F2.rats..The.combined.
F1.and.F2.data.were.reviewed.to.determine.the.occurrence.of.these.alterations.on.a.per.animal.
and.per.litter.basis.across.the.dose.range,.as.shown.in.Table.23..Based.on.the.incidence.of.small.
reproductive.organ.size.at.necropsy,.the.Expert.Panel.considered.300.ppm.(about.14.–.23.mg/kg.
bw/day).to.be.an.effect.level,.giving.a.NOAEL.of.100.ppm,.about.3.–.5.mg/kg.bw/day.]
A multiple dose study in rats by Shirota.et.al..(112) was designed to evaluate testicular pathology after intrauterine exposure to DEHP. Pregnant Sprague-Dawley rats were given gavage doses of DEHP in corn oil on GD 7 – 18 at 0, 500, or 1000 mg/kg bw/day in 1 experiment and 0, 125, 250, or 500 mg/kg bw/day in a second experiment. Decreased fetal weight and increased intrauterine mortality were noted at 1000 mg/kg bw/day. Postnatal findings included changes in pup weight at 250 and 500 mg/kg bw/day and increased incidences of multinucleated germ cells at ≥ 125 mg/kg bw/day and interstitial hyperplasia at 250 and 500 mg/kg bw/day.
Jarfelt.et.al..(117) evaluated the effects of perinatal exposure of groups of 20 Wistar rats to DEHP with or without diethylhexyl adipate. Timed-mated pregnant animals were treated by gavage from GD 7 to PND 1 with vehicle control, DEHP 300 mg/kg bw/day, DEHP 750 mg/kg bw/day, or DEHP 750 mg/kg bw/day + diethylhexyl adipate 400 mg/kg bw/day (n = 20/group). Litters were raised by their dams until weaning on PND 21, after which 1 male and 1 female per litter were retained. Recorded endpoints included anogenital distance on PND3, retention of nipples/areolae on PND13, onset of vaginal opening and balano-preputial separation, and epididymal sperm parameters and testicular histopathology on PND 190. Non-retained pups and dams were killed on PND 22 and evaluated for macroscopic lesions, and 3 – 5 males/litter underwent histopathologic/immunocytochemical examination of the testes. Increased postimplantation loss, reduced anogenital distance, and increased incidence of retained nipples were significantly different at all levels of DEHP exposure. There was also evidence of increased incidence of abnormal testes histology at both levels of DEHP exposure.
Effects noted in numerous single dose-level studies were consistent to those observed in the multiple dose-level studies summarized above. Although testicular weight and histology were not affected in offspring of rats treated with 100 mg/kg bw/day DEHP during pregnancy or lactation (111), treatment of rats with DEHP 750 mg/kg bw/day in late pregnancy and/or early lactation resulted in decreased testicular weights and testicular lesions in offspring (121, 123). Nipples and reduced anogenital distance were repeatedly observed in male offspring exposed to 750 mg/kg bw/day DEHP during
Appendix II
gestation or lactation (115, 121). Additional observations in male offspring of rats dosed with 750 mg/kg bw/day during late pregnancy and early lactation were lack of testicular descent, agenesis of accessory reproductive organs, and incomplete preputial separation (121).
A number of studies examined mechanisms of DEHP toxicity. Single dose-level studies with exposures during gestation and/or lactation and examination of fetal or immature rats consistently demonstrated reductions in blood testosterone levels at ≥ 100 mg/kg bw/day DEHP (111, 115), Leydig cell testos-terone production at ≥ 100 mg/kg bw/day (111), testicular testostestos-terone content at ≥ 300 mg/kg bw/day (115, 123), and ex vivo testicular testosterone production at ≥ 750 mg/kg bw/day (115, 123, 124). One of the studies indicated that reductions in testosterone production observed shortly after exposure in neonatal or weanling rats were no longer present in adulthood (111).
Evidence that DEHP targets Leydig cells, gonocytes, and Sertoli cells was noted following gestational and lactational exposure of rats to ≥ 100 mg/kg bw/day DEHP (111, 119, 123). MEHP, but not 2-ethyl-hexanol, was found to cause increases in large multinucleated gonocytes and to inhibit Sertoli cell proliferation (119). An in vitro study demonstrated that gonocytes and Sertoli cells are susceptible to MEHP-induced toxicity during periods of proliferation (130). In 1 study, DEHP doses ≥ 750 mg/kg bw/day during gestation in rats reduced testicular expression of insulin-like hormone 3, a hormone produced by Leydig cells and possibly involved in development of the gubernaculum (124).
Liu.et.al..(125) evaluated gene expression profiles in the GD 19 fetal testis after GD 12 – 19 gavage treat-ment of dams with 1 of 7 phthalates (n = 5/group) or with corn oil vehicle (n = 10; vaginal sperm = GD 0).
The phthalates were DEHP or diethyl, dimethyl, dioctyl tere-, dibutyl, dipentyl, or benzyl butyl phthalate at a dose level of 500 mg/kg bw/day. On GD19, pups were evaluated for anogenital distance and testes were processed for gene expression profiles for 3 pups/treatment group, each from a different litter.
Anogenital distance was significantly reduced by pregnancy treatment with DEHP, dibutyl phthalate, benzyl butyl phthalate, and dipentyl phthalate. Dimethyl, diethyl, and dioctyl terephthalate did not affect anogenital distance. Of 391 significantly altered gene probe sets, there were 167 characterized sequences. Genes related to lipid, sterol, and cholesterol homeostasis accounted for 31 of these 167 genes. There were also 10 genes involved in lipid, sterol, and cholesterol transport, 12 genes involved in steroidogenesis, 9 transcription factor genes, 22 signal transduction genes, 11 genes involved in oxidative stress, and 13 genes related to the cytoskeleton. In general, there was a similar pattern of gene expression profile with those phthalates that altered anogenital distance as compared those that did not, suggesting that these phthalates operate by a common mode of action on the developing testes.
Targeted pathways were directly or indirectly related to Leydig cell production of testosterone and pathways important for Sertoli cell-gonocyte interaction.
Appendix II
Table 28. Summary of DEHP Effects on Developmental Toxicity Species and StrainTreatmentEffect Levels (mg/kg bw/day) NOAEL Maternal LO
AELDevelopmental Reference LOAELBMDLa Sprague-Dawley RatOral 0, 375, 750, or 1500 mg/kg bw/day GD 3 to PND 21.
Maternal: 375 Developmental: NAb
750 (↓ prenatal weight gain)
375 (↑ in areolae or nipples,
incomplete preputial separation, non-descent of testes, and agenesis of anterior prostate) 10% Level: 167 (↓ epididymal sperm) 1 SD Level: 135
(PND 105 epididymis weight)
Moore et al. (113) Sprague-Dawley RatGavage 0, 20, 100, 200, or 500 mg/kg bw PND 3 (Day of birth = PND 1)Developmental: 20NA
100 (Li et al. (119) ↓ Sertoli cell proliferation) WistarFeed Rat 0, 1000, 3000, and 9000 ppm (0, 113, 340, and 1088 mg/kg bw/day) During gestation and lactation
Maternal: 340 Developmental: 113
1088 (↓ feed intake and body weight gain)
340 (↑ pre- and postnatal mortality,↓ body weight, altered male anogenital distance, and retained nipples/areolae)
10% Level: 231 (F2 pup survival on PND 0 – 4)
Schilling et al. (151)
Discussed in Section 4.
Sprague-Dawley RatGavage 0, 300, or 600 mg/kg bw/day 19 – 21 days beginning at 3 – 5 days of age.
Examination immediately after dosing:Cammack et al. (120) NA 300 (depletion of ger
minal epithelium and/or ↓ seminiferous tubule diameter and ↓ absolute testes weight)
10% Level: 77.4 1 SD Level: 628 (testis weight) Examination at 90 days of age: Developmental: < 300
300 (↓ in seminiferous tubular diameter, ↓ absolute testis weight)
10% Level: 125 1 SD Level: 65
Appendix II
Species and StrainTreatmentEffect Levels (mg/kg bw/day) NOAEL Maternal LOAELDevelopmental Reference LOAELBMDLa Sprague-Dawley RatIV 0, 60, 300, or 600 mg/kg bw/day 21 days beginning at 3 – 5 days of age.
Examination immediately after dosing:Cammack et al. (120) Developmental: 60
300 (depletion of germinal epithelium and/or ↓ seminiferous tubule diameter, ↓ absolute testes weight, and ↑ absolute liver weight)
10% Level: 106 1 SD Level: 125 (testis weight) Examination at 90 days of age: Developmental: 60
300 (10% Level: 190 ↓ absolute testis weight) 1 SD Level: 105 (testis weight) Sprague-Dawley Feed Rat 1.5, 10, 30, 100, 300, 1000, 7500, or 10,000 ppm (0.09 – 0.12, 0.5 – 0.8, 1.4 – 2.4, 4.8 – 7.9, 14 – 23, 46 – 77, 392 – 592, and 543 – 775 mg/kg bw/day)
Study authors: Maternal: 46 – 77 Development: 46 – 77
Study authors: 392 – 592 (body weight changes)
Study authors: 392 – 592 (Pregnancy indices, litter data)
10% Level: 33 – 56 1 SD Level: 45 – 75 (F3 sperm/cauda)
The National Toxicology Program (114) Expert Panel: Maternal: 46 – 77 Developmental: 3 – 5
Expert Panel: 392 – 592 (↓ body weight gain)
Expert Panel: 14 – 23 (combined F1 and F2 gross observations of small reproductive organs) Sprague-Dawley RatGavage 500, and 1000 (Experiment 1) 0, or 0, 125, 250, and 500 mg/kg bw/day (Experiment 2) GD 7 – 18
Maternal: 500 Developmental: 5001000 (↓ maternal body weight)
1000 (↑ intrauterine mortality, ↓ live fetuses/litter).
10% Level: 334 1 SD Level: 490 (↓ live fetuses)
Shirota et al. (112)
Appendix II
Species and StrainTreatmentEffect Levels (mg/kg bw/day) NOAEL
Maternal LO
AELDevelopmental Reference LOAELBMDLa Wistar RatGavage GD 7 – 17 at 0, 300, or 750 mg/kg bw/day.
Maternal:≥ 750 Developmental: NANA
300 (postnatal death, male ano- genital distance, retained nipples, abnormal testis histology)
10% Level: 13
(postimplantation loss) 1 SD Level: 179 (male anogenital distance)
Jarfelt et al. (117) Wistar RatGavage 0, 300, or 750 mg/kg bw/day GD 7 – PND 17
Maternal: ND Developmental: 300NDc
750 (plasma hor
mone changes)
Not calculable from data in study report.Borch et al. (115) Gavage 0, 300, or 750 mg/kg bw/day GD 7 – PND 17
Maternal: ND Developmental: < 300ND
300 (↑ apoptosis in fetal tissue)
Not calculable from data in study report.Borch et al. (118) CD-1 MouseFeed 0, 17, 47, and 140 mg/kg bw/day dur- ing gestation, 0, 60, 172, and 493 mg/kg bw/day During lactation 0, 16 – 19, 48 – 56, and 145 – 171 mg/kg bw/day From weaning to 9 weeks of age in F1 offspring.
Maternal: 140 – 493 Developmental: 47 – 172 NA140 – 493 (↓ survival during lactation period)
Tanaka (133) a See the footnote to Table 20 for definitions and a discussion of the use of benchmark dose in this report. b NA: Not applicable; c ND: Not Determined
Appendix II
ConClusIons bAseD onlY on lITerATure APPeArIng sInCe The fIrsT exPerT PAnel rePorT
There.is.insufficient.evidence.in.humans.that.DEHP.causes.developmental.toxicity.when.
exposure.is.prenatal..While there was one human study (108) judged to be useful, it was not sufficient to draw conclusions regarding developmental toxicity following prenatal exposure. The study found no significant association between maternal prenatal urinary MEHP and anogenital index in male offspring, and the interpretation of this novel index as applied to humans has not been established.
There.is.insufficient.evidence.in.humans.that.DEHP.causes.developmental.toxicity.when.
exposure.is.during.childhood..While there were two human studies judged to be useful, they were not sufficient to draw conclusions regarding developmental toxicity. One study (109) had very small sample size with no measurement of exposure. The other study (17) was limited in size and by the possibility of contamination by breast pump use.
There.is.sufficient.evidence.that.DEHP.exposure.in.rats.causes.developmental.toxicity.with.
dietary.exposure.during.gestation.and/or.early.postnatal.life.at.14.–.23.mg/kg.bw/day.as.
manifested.by.small.or.absent.male.reproductive.organs.(114). There were multiple other studies supporting effects on the developing male reproductive tract at higher dose levels. The critical period for effects on the testes extends into the immediate postnatal period (120) with decreased Sertoli cell proliferation seen in male rats exposed by oral gavage to DEHP 100 mg/kg/day on PND 3 (119).
There.is.sufficient.evidence.that.DEHP.causes.developmental.toxicity.with.21.days.of.IV.
exposure.starting.at.PND.3.–.5.at.300.mg/kg/day.as.manifested.by.decreased.testes.weight,.
depletion.of.germinal.epithelium,.and.decreased.seminiferous.tubule.diameter.(120)..The reduced testicular weights persisted through at least 90 days of age. These findings are consistent with those observed after oral exposure.
These data are assumed relevant to assessment of human risk.
NOTE: The definitions of the term sufficient and the terms assumed relevant, relevant, and not relevant are in the CERHR guidelines at http://cerhr.niehs.nih.gov/news/guidelines.html.
Appendix II
ConClusIons froM The orIgInAl exPerT PAnel evAluATIon
The original Expert Panel report on DEHP contained conclusions about developmental toxicity in Section 5. These conclusions have been extracted and reproduced below, with the section numbering as found in the original document. The references listed in the conclusion are listed, and the table to which the conclusions refer is reproduced, numbered Table 71 as in the original.
5.1.3
There were no studies located on the developmental toxicity of DEHP or its metabolites in humans.
5.1.3.1
Developmental toxicity findings were remarkably consistent. DEHP was found to produce malfor-mations, as well as intrauterine death and developmental delay. The pattern of malformations seen in fetuses is consistent across studies. It included morphological abnormalities of the axial skeleton (including tail), cardiovascular system (heart and aortic arch), appendicular skeleton (missing limb bones, finger abnormalities), eye (including open eye), and neural tube (exencephaly).
In general, across studies there was not a strong relationship between the type and amount of maternal toxicity and developmental toxicity.
In addition to the studies of developmental toxicity with post-conception exposure discussed above, developmental toxicity was also manifested in reproductive toxicity studies . . .. The database as a whole identified CD-1 mice as the most sensitive species for DEHP developmental toxicity via the oral route. The critical papers are [149,150,168,186]. LOAELs and NOAELs for some relevant developmental toxicity studies are presented in Table 71. Developmental effects in reproduction studies are listed in Table 76 [See.Section.4.of.this.report.] Studies that address developmental toxicity are consistent in identifying the lower effective range of oral exposure, taking into account differences in duration of treatment.
The DEHP database contains four rat studies conducted by a route other than oral: an IV study, two IP studies, and an inhalation study. These studies provide valuable information but do not contain enough data for separate route-specific hazard identification and NOAEL/LOAEL selection.
The panel is not confident that the lowest dose has been established at which developmental toxicity (the development of the male reproductive system) occurs.
5.1.3.6
The database provides adequate information to identify DEHP as a developmental toxicant by the oral route and for identification of NOAELs and LOAELs for dose – response assessment.
Appendix II
The data are also sufficient to identify the metabolites (MEHP, 2-EH, 2-EHA) as developmental toxicants. However, there are not enough studies for independent hazard identification and dose – response assessment for the parenteral route. Because of the known role of intestinal lipase in DEHP metabolism, it is not possible to readily generalize dose – response assessment from the oral to intravenous route. Existing PBPK models do not include fetal compartments;
and hence have limited use at present.
5.2
As will be discussed below, there are sufficient data in rodents to conclude confidently that oral exposure to DEHP can cause reproductive and developmental toxicity in rats and mice. Further, an effect observed in rats involves adverse effects on the development, structure, and function of the male reproductive tract. Thus, for DEHP, the effects on reproduction and development are intertwined.
The developmental toxicity database contains well-conducted and reported studies, many avail-able as full GLP study reports, and additional, more restricted studies that provide supplemental and supportive information. The database is somewhat limited in that it consists almost entirely of studies in rats and mice orally exposed during gestation where effects are seen by examining physical development of rodent pups just prior to birth (i.e. prenatal assessment). These studies indicate that a range of effects may occur, including malformations (tail malformations, axial and appendicular skeletal abnormalities, cardiovascular malformations, and neural tube closure defects), developmental delays, and intrauterine death. The NOAEL based on malformations in rodents was ~ 40 mg/kg bw/day and a NOAEL of 3.7 – 14 mg/kg bw/day was identified for testicular development/effects in rodents. In contrast, functional reproductive endpoints that are evaluated through postnatal observation have not been adequately studied. This is a significant data limitation. There are a limited number of studies by the inhalation, dermal, and intravenous administration routes. It was noted that results are consistent across studies, taking into account doses, route, species, timing,
The examination of effects during the late gestational and neonatal periods is quite recent and incomplete. Despite the general belief among expert panel members that this represents a time of potentially high sensitivity to DEHP-induced disruption of the reproductive system, the dose – response relationships for reproductive effects following exposures in gestational versus postnatal ages are unknown. Low-dose studies examining sensitive endpoints following late gestational exposure are a critical data need.
There is a study that demonstrated the same spectrum of developmental toxicity (as seen in
‘normal’ mice) in mice that were genetically incapable of expressing peroxisome proliferation due to lack of PPAR-alpha.
DEHP data from rats and mice are assumed relevant to judging hazard to human reproduction and development; they are the standard mammalian test systems used.
Appendix II
referenCes froM The orIgInAl rePorT CITeD Above
[146] Price CJ, Tyl RW, Marr MC, Myers CB, Sadler BM, Kimmel CA. Reproduction and fertility evaluation of diethylhexyl phthalate (CAS No. 117-81-7) in CD-1 mice exposed during gestation. Research Triangle Park, NC: National Toxicology Program, 1988.
[149] Tyl RW, Price CJ, Marr MC, Kimmel CA. Developmental toxicity evaluation of dietary di(2-ethylhexyl)phthalate in Fischer 344 rats and CD-1 mice. Fundam Appl Toxicol 1988;10:395 – 412.
[150] Huntingdon HLS-A. Phthalic acid, di(2-ethylhexyl) ester (DEHP): study of embryo-foetal toxicity in the CD-1 mouse by oral gavage administration. Report no.: 95/EHM007/0705, 1996.
[156] Price CJ, Tyl RW, Marr MC, Sadler BM, Kimmel CA. Reproduction and fertility evalua-tion of diethylhexyl phthalate (CAS No. 117-81-7) in Fischer 344 rats exposed during gestaevalua-tion NTP 86-309. Research Triangle Park, NC: National Toxicology Program, 1986.
[168] Lamb IV JC. Reproductive effects of four phthalic acid esters in the mouse. Toxicol Appl Pharmacol 1987;88:255 – 69.
[185] Tyl R, Price CJ. Teratological evaluation of diethylhexylphthalate (CAS No. 117-81-7) in CD-1 mice. In: Jefferson AR, editor i.n National Center for Toxicological Research, 1984.
[186] Reel JR, Tyl RW, Lawton AD, Jamb JC. Diethylhexyl phthalate (DEHP): Reproduction and fertility assessment in CD-1 mice when administered in the feed. PB84-181734.
Springfield, VA: available from: NTIS, Research Triangle Park: National Toxicology Program,1984.
Appendix II
Table 71. Summary of DEHP Effects in Developmental Toxicity Studies with Oral Exposure
Protocol & Doses NOAEL (mg/kg bw/day)
LOAEL (mg/kg bw/day)
Fetal Effects at Higher Doses Maternal
Developmen-tal Prenatal feeding study
in CD-1 mice. 30/group received 0, 44, 91, 191, or 293 mg/kg bw/day on GD 0−17. Dams and pups examined in late gestation.
[149, 185]*
Maternal: 44 Developmental: 44
91
Clinical signs
↓ Weight gain 91
↑Skeletal, visceral, and external mal-formations
↑ Skeletal, visceral, and external malformations
↑ Prenatal mortality
↓ Fetal weight
Prenatal gavage study in CD-1 mice. 14 /group received 0, 40, 200, or 1,000 mg/kg bw/day on GD 6−15. Dams and pups examined in late gestation.
[150]*
Maternal: 200 Developmental: 40
1000
↑ Liver weight
↓ Weight gain 200
↑ Visceral and external variations and malformations
↑ Skeletal, visceral, and external variations and malformations
↑ Prenatal mortality
Prenatal feeding study in Fischer 344 rats. 20/group received 0, 164, 313, or 573 mg/kg bw/day on GD 0−20.
Pups evaluated postnatally.
[156]*
Maternal: 164 Developmen-tal: 164
313
↓ Food Intake 313
↑ Prenatal mortality
↑ Prenatal mortality
↓ Pup body weight on PND 1 only
Prenatal feeding study in CD-1 mice. 28/group re-ceived 0, 19, 48, or 95 mg/
kg bw/day from GD 0−17.
Pups evaluated postnatally.
[146]*
Maternal: 95 Developmental: 48
No higher doses
95
↑ Prenatal mortality
↓ Pup survival o n pnd 4
No higher doses
*Doses calculated by study authors.